Zynga expands development of tablet and smartphone games

Zynga has purchased four mobile game companies in an effort to expand development of tablet and smartphone games.

David Ko, Zynga’s top mobile executive, told Reuters that in December it acquired Gamedoctors, the maker of ZombieSmash.

The studio that created the iOS game World of Goo, Page44 Studios, was also bought by Zynga back in September. Before that, the company acquired game companies HipLogic and Astro Ape Studios.

Ko declined Reuters any comment on the size of the deals.

Zynga’s early success on the Facebook platform hasn’t yet translated to mobile devices, where Walt Disney Co. and Electronic Arts Inc. have been stiff competition, releasing hit games of their own. Only time will tell if these acquisitions make a name for Zynga in the mobile arena.